Luminaire



Sept. 17, 1940.

J. A. O'NEIL,

LUMI'NAiRE Find Nov. 26., 1938 2 Sheets-Sheet 1 v Inventor James A.O'Neil,

by 752/14 6. His Attorney.

J. A. O'NEIL LUMINAIRE Sept. 17, 1940.

Filed Nov. 26, 1938 2 Sheets-Sheet 2 Inventor James A. O'Neil, 139164476 His Attorney.

Patented Sept. 17, 1940 arisen James A. ONeil, Lynn, Mass., assignor toGeneral Electric Company, a corporation of New York Application November26, 1938, Serial No. 242,519

1 Claim.

My invention relates to luminaires and more particularly to an improvedcombination of reflector and deflector for highway lighting luminaires.

One object of my invention is to provide an asymmetric distribution oflight from a normally symmetric luminaire.

For a better understanding of my invention together with other andfurther objects thereof, reference is had to the following descriptiontaken in connection with the accompanying drawings, and its scope willbe pointed out in the appended claim.

In the accompanying drawings, Fig. 1 is a side elevation, partly insection, of a luminaire built in accordance with my invention; Fig. 2 isa plan elevation of a deflector used in the luminaire of Fig. 1; Fig. 3is a back elevation of this deflector; Fig. 4 is aside elevation of aluminaire, partly in section, provided with a modified deflector; Fig. 5is a plan elevation of the modified deflector; and Fig. 6 is a frontelevation thereof.

Referring to the drawings in detail, Fig. 1 discloses a luminairecomprising a cap H], a reflector H and a globe l2. The reflector II isattached to the cap Ill by latches I3 and the globe I2 is attached tothe reflector H by a flange M, on the edge of the reflector H, which isrolled over a corresponding flange on the edge of the globe l2. Thereflector H is of sheet metal and is preferably in the form of a conoid,the profile curvature of this conoid being a combination of a parabolaand ellipse. The reflector herein described is used merely by wayofexample. My invention may be applied to any conoidal reflectorprojecting a comparatively wide beam.

The reflector being circular in horizontal cross section, projects asymmetrical beam from a light source located on its focal axis. In theparticular illustration, the angular spread of this beam isapproximately 160, the center of the light source being above the edgeof the reflector so that a line drawn from the edge to the source isbelow horizontal. The light source is an incandescent lamp is supportedin the cap l0, and projecting downwardly so that the filament is in thefocal point of the reflector. It is practically impossible to obtain thehighest candle power at the virtual cutoff, or at the edge of the lightbeam in luminaires of this type, and in the present luminaire thisregion of maximum candle power is approximately 72 from the vertical, or8 inside the edge of the beam.

are installed on city streets or on highways, they (Cl. MAL-) aresuspended from horizontal arms attached to poles which are located alongthe edge of the street or highway. Since it is impractical to have thesehorizontal arms of great length, the luminaires are nearer to one sideof the street 1 than to the other, and since the light distribution issymmetrical, the light is projected through the windows of houses alongthe edge of the street. This is objectionable, and hence it is desirableto provide some means to prevent this projection of light into adjacenthouses and to redirect it onto the street surface where it is needed. Inaccordance with my invention, this redirection of light is accomplishedboth by a novel deflector and by its novel combination with thesymmetrical reflector of a luminaire.

In Fig. 1 I have indicated by lines l6, ll and i8 the approximatedistribution of light from the lamp if; by the reflector H in any axialplane. This distribution is, of course, symmetrical about the axis ofthe reflector. These lines indicate that a parallel beam is projected,by the parabolic section of the reflector surface, between the lines itand l! directly across the unit and below the edge of the reflector onthe opposite side, and a second wedge-shaped beam is projected from theupper, or elliptical, section of the reflector between the lines ii andi8, this beam having a focal region at E9 beyond which it again spreadsand adds to the light flux of the parallel beam.

In order to redirect this light onto the street surface, and therebyprotect the homes near each one of these luminaires, a novel shapeddeflector 29 is mounted by brackets 2i and 2! within the reflector H andthe globe l2. This deflector is made of sheet metal, preferablyaluminum, having its surface treated to retain a maximum efficiencyreflecting surface and is given a profile curvature of a parabola whosefocus is on the reflector axis and in the center of the light source it.This curve is revolved about its focus and the axis of the reflector itover an arc of approximately l80". The axis of this parabola profilecurve is 18 to the horizontal, whereby the light impinging upon thisdeflector is reflected in the direction of the maximum candle power ofthe beam projected by the reflector. This is illustrated by thereflection of ray H in the direction of ray ll. The semi-conoidalsurface thus formed projects light into the region of the highest candlepower of the beam. It is within the scope of my invention, however, toproject this deflected light evenly throughout the beam, or in any otherdesired proportion, by using a curvature similar to the profile curve ofthe reflector, or any other suitable curve, in generating the deflectorsurface.

Due to the curvature and the method of generating the surfaces of thedeflector, it tapers towards each end from a center section. Inaccordance with another phase of my invention, this deflector surface ismounted within the symmetrical reflector, so that its maximum width isat a point slightly below the edge of the reflector, and is permitted totaper to a point below the reflector. It is permitted to extend abovethis maximum width section into the reflector, being cut ofihorizontally in a plane above the reflector edge, this plane being highenough to prevent the projection of any light beyond this deflector fromany section of the reflector. The deflector is spaced from the surfaceof the luminaire so that a certain amount of light flux will be directedto the reflector and globe from whose surfaces it will be redirectedonto the back of the deflector so as to eliminate the totally black spotwithin the luminaire resulting from the presence 5 of this deflector inthe globe. The upper horizontal edge of the deflector 20 is placedWithin the reflector so that it intersects the line l8 which marks theupper edge of the reflector beam projected toward the house side of theluminaire,

thereby cutting off a sector of the light beam projected in thatdirection and reflecting it in the directionof line l8 whichapproximately coincides with the deflector axis. The lower end of thedeflector terminates in an apex on the axis of the reflector so that thesector of the beam that is redirected is actually wedge shaped, being180 at the edge of the reflector beam and tapering off to zero at theaxis of the reflector. The result of this is' that the beam is deflectedat its upper edge, where it is most objectionable, over a sector of 180.At the lower angles an increasingly greater portion of the light isallowed to spill, or project, toward the house side of the street. Thislight, however, being directed at lower angles, does not reach thehouses near the luminaire. The edge of the deflector cuts off the beamso that it ends approximately along the edge of the street. Some of thislight is also reflected by the globe onto the back surface of thedeflector, thereby eliminating the shadow which this deflector wouldotherwise throw onto the globe and thereby mar the appearance of theluminaire.

' In Figs. 4, 5 and 6, I have illustrated a modified deflector in thesame unit as is illustrated in Fig. 1. The deflector 25 in thismodification is generally of the same 'semi-conoidal shape as thatillustrated in Figs; 1, 2 and 3. It is reinforced, along its edge, by'aflange 26 and is provided with an opening 21. This opening is centrallylocated and substantially divides the deflector into two sections aboveits center. The light projecting through this opening is redirected bycylindrical deflectors 28 and 29. These two deflectors are formed from asingle sheet of metal having their central common edge attachedto thedeflector by a rivet 30. Their respective surfaces are parabolic, beinggenerated by a straight line which is moved parallel to the axis of thereflector. They are supported at their outer ends by a third deflector3|. The

cylindrical deflectors 28 and 29 project the light coming through theopening in the first deflector at approximately right angles to theopening in two opposite directions. Some of this light also reaches theback surface of the deflector 25, thereby more efficiently hiding itspresence within the luminaire. A greater portion of this light isprojected, as above stated, at right angles to the opening, and when theluminaire is properly installed, this light is projected parallel to theaxis of the highway and along the edge thereof. The third cylindricaldeflector 3| acts as a support for the cylindrical deflectors 28 and 29and also reflects some of the stray light flux projected toward it. Thislast deflector is circular and any light reaching its inner surface isprojected to the back surface of the deflector 25. This completeassembly of deflectors is mounted within the reflector II by brackets 32and 33 in such manner that the relationship of the deflector 25 to thereflector ll remains the same as the relationship between the reflectorH and the deflector 20, i. e-., the. axis of the semiconoidal deflectorcoincides with the axis of the reflector, the edgesthereof are in aplane with the reflector axis and the axis of the deflector curveintersects the focal point of the reflector.

The above-described reflector and deflector combination comprises asimple inexpensive structure for obtaining an asymmetrical distributionof light flux from a symmetrical luminaire. It is impractical from amanufacturing standpoint to modify the reflectors of the luminaires soas to obtain the desired asymmetrical light distribution for eachinstallation. With my improved deflectors, however, and their improvedcombination with the symmetrical reflector, the desired asymmetricaldistribution is obtained economically and without altering the normalappearance of the luminaire.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

In a luminaire having a light source a conoidal reflector interceptingsubstantially 200 of the light flux projected from said source and beingarranged to project a beam which is symmetrical about the axis of saidlight source, the combination of a deflector, said deflector comprisinga conoidal surface having an arcuate length of approximatel 180 aboutthe axis of said reflector and extending above and below the edge ofsaid reflector, said deflector terminating in an apex below saidreflector, an opening in said deflector extending from the upper end ofsaid deflector. to a predetermined point below the edge of saidreflector and cylindrical deflecting surfaces spaced from said firstdeflector arranged to intercept the light projected through said openingand to redistribute said light in opposite directions along an edge ofthe combined beam projected by said luminaire.

JAMES A. ONEIL.

